Previous Issue: February 2014

The Prognostic Utility of Degenerative Left Shifts in Dogs

The degenerative left shift (DLS) is a pattern seen on haematology samples indicating the presence of an increased number of immature neutrophils, and the presence of toxic changes. This is considered to be a poor prognostic indicator, but there is little evidence to support this in dogs. This retrospective case-control study compared survival in 319 dogs with DLS to 918 dogs without DLS. Half of DLS cases survived to discharge compared to 76% of controls. DLS was found to be a significant predictor of death or euthanasia. However, the authors note that this findings varies with diagnosis, and the circumstances of the individual patient should be taken into consideration.

Bottom line: The finding of degenerative left shift on haematology in dogs is a negative prognostic indicator.

Obstructive airway syndrome is common in brachycephalic breeds, but the Norwich Terrier, a non-brachycephalic breed, is reported to suffer from respiratory problems. This study characterised obstructive airway syndrome in this breed. 16 Norwich Terriers were included, 12 with and 4 without clinical signs of respiratory disease. Physical examinations and laryngoscopy were performed in all cases. Of the twelve dogs presenting with respiratory problems, 11 had an abnormal laryngoscopic examination, with abnormalities including redundant supra-arytenoid folds, laryngeal collapse, everted laryngeal saccules and a narrowed laryngeal opening. Of the four dogs without clinical signs, three had similar appearances of the larynx to affected dogs. Improvement after surgery was minimal to moderate. The authors conclude that Norwich Terriers suffer from an upper airway obstructive syndrome that is different from that seen in brachycephalic breeds, and note that in these cases the physical examination is often normal. They caution care when anaesthetising this breed because of the narrow laryngeal openings.

Bottom line: The Norwich Terrier is predisposed to a form of upper airway obstructive syndrome.

Injection site sarcomas are rare but serious neoplasms which can be very extensive locally. The extent of the tumour can be visualised on MRI, and so MRI is often recommended for staging and surgical planning purposes. This retrospective study described the low field MRI characteristics of confirmed injection site sarcomas in 19 cats. MRI findings, thoracic radiographs, histological findings and medical records of these cats were reviewed. The results showed that cats with multiple tumours were more likely to have had a previous excisional biopsy and were less likely to undergo definitive surgery. On MRI, the tumours were hyperintense compared to the surrounding musculature on both T1 and T2 weighted series, and larger tumours were more likely to be mineralised. Most tumours showed moderate to marked heterogenous contrast enhancement.

Bottom line: The authors note that the low field MRI characteristics of injection site sarcoma can vary widely and are affected by previous biopsies.

Use of prednisolone as monotherapy in the treatment of feline pemphigus foliaceus: a retrospective study of 37 cats
Simpson, D. L. and Burton, G. G. (2013)Veterinary Dermatology, 24: 598–e144.

Pemphigus foliaceous is an autoimmune skin condition that can affects cats. In some countries, prednisone is used to treat this condition. This retrospective study assessed the success of using prednisolone instead of prednisone to treat the condition. Thirty seven cats with pemphigus foliaceous were treated with prednisolone as a monotherapy. Their records were analysed for history, clinical signs, histological and/or cytological findings and results of staining and fungal culture, as well as response to immunosuppressive therapy. 97% of cases achieved complete remission within 8 weeks of starting therapy with a median induction dose of prednisolone 2mg/kg daily. In those cases that required ongoing therapy, prednisolone monotherapy was sufficient to maintain remission in 67% of cases, with a median maintenance dose of 1.2mg/kg/week. In 14% of cases it was possible to eventually discontinue medication. Adverse effects were uncommon.

Prolapse of the nictitating membrane gland is a common problem in certain breeds
of dog. This study investigated the inheritance of the condition by examining the pedigrees of two lines of purpose-bred mongrel dogs. The first line (GS) was derived from one German Shorthaired pointer and seven mongrel dogs. The second line (M) was established from one mongrel dog and three miniature long-haired dachshunds. One female dog contributed to both lines. The prevalence of prolapsed nictitating membrane glands in the GS line was 4% in a 12 year period, and 10% in the M line over 6 years. Pedigree analysis ruled out simple modes of inheritance in both lines.

Bottom line: Prolapse of the nictitating membrane gland appears to have genetic risk factors, and although the exact mode of inheritance is not yet known, it appears to be complex and possibly multigenic.

Peripheral intravenous catheters are prone to problems such as infections and blockage due to the formation of clots. Many clinicians recommend regularly flushing the catheters with heparinised saline to reduce complications. This prospective blinded randomised study aimed to determine whether there was a benefit to flushing iv catheters with heparinised saline or 0.9% sodium chloride. Thirty healthy dogs were randomised into 2 treatment groups and a control group. An 18 gauge catheter was placed into the cephalic vein of each dog. In the treatment groups, dog were randomised to have their catheter flushed with heparinised saline or sodium chloride every 6 hours for 42 hours. Each catheter was evaluated for patency by aspirating blood prior to each flush, and the catheter site was assessed for signs of phlebitis. There was no significant difference between the two treatment groups for aspiration of blood, and dogs in the control group had catheters that were easily flushed except one dog. No cases showed signs of phlebitis.

Bottom line: 0.9% sodium chloride was as effective as 10IU/ml heparinised saline in maintaining catheter patency in this study.

Portosystemic shunts are congenital or acquired vessels that allow venous blood to bypass the liver, reducing liver function. They can be suspected from dynamic bile acid testing, but imaging is necessary to definitively identify them. Imaging methods include ultrasound which is technically difficult and highly operator dependent, and mesenteric portovenography, which is invasive. This retrospective study compared computed tomographic angiography (CTA) and ultrasonography for the detection of portosystemic shunts. 76 dogs that had CT and/or abdominal ultrasonography had their medical records reviewed. CTA was 96% sensitive for portosystemic shunts compared to 68% for ultrasonography. Specificity was 89% for CTA and 84% for ultrasonography. CTA was more accurate in identifying the correct origin and insertion of the shunt vessel. Multiple acquired portosystemic shunts were identified more frequently with CTA than ultrasonography.

Bottom line: Computed tomographic angiography is non-invasive and appears to be superior to abdominal ultrasonography for the detection and characterisation of portosystemic shunts in dogs.

Selective-serotonin reuptake inhibitors (SSRIs) are common drugs in human medicine, used in the treatment of psychological disorders, and accidental ingestion can occur in pets. This retrospective study examined the effects of SSRI toxicosis on 33 cats which had been witnessed to ingest an SSRI. Venlafaxine and fluoxetine were the most common SSRIs ingested. 76% of cases remained asymptomatic. Of those that showed clinical signs, 75% showed signs of sedation, 50% showed signs of gastrointestinal signs, and occasional signs of CNS stimulation, cardiovascular signs and hyperthermia were noted. Hospitalised patients were treated with medications including intravenous fluids, activated charcoal, anti-arrhythmics, methocarbamol and cyproheptadine. All symptomatic cats had complete resolution of signs and were discharged.

Bottom line: SSRI ingestion has an excellent prognosis in cats. Decontamination and supportive care for 12-24 hours should be considered.

This study compared complications and survival rates with three different anastomosis methods following proximal ileal resection; namely jejunojejunostomy, jejunoileostomy and jejunocaecostomy. 112 horses were included; as this was a retrospective study the surgical procedure was not randomised but was based on lesion type and surgeon preference. Short-term outcome was measured by survival to discharge and was not different between groups. Those who underwent a jejunoileostomy were more likely to have a repeat celiotomy during the period of hospitalisation. Long term follow up was measured using a Kaplan-Meier estimate of survival function and found that horses who had undergone a jejunocaecostomy were more likely to have repeated episodes of colic and were less likely to survive long term than those who had undergone one of the alternative procedures. Survival following jejunoileostomy at one-year follow up was 100%, compared with 97% for jejunojejunostomy and 83% for jejunocaecostomy. The authors also noted that anastomosis pattern may reflect outcome, with a double layer appositional pattern performing best although numbers were too low to be of statistical significance.

Bottom line: This study concluded that following proximal ileal resection, jejunoileostomy may be anastomosis technique of choice due to better long term survival rates and lower prevalence of colic in the long term.

This retrospective cohort study investigated the effect of injury to the suspensory branch insertion in juvenile racehorses. The records of 896 horses were reviewed, cases were included if they had evidence of injury to one suspensory branch insertion in one limb which was managed conservatively, prior to starting their racing career. Matched controls were established by comparing the race records of a maternal sibling with each case. Racing and performance data were used to compare the ability of cases to start a race compared with their cohorts. The study found that the prevalence of insertional suspensory branch desmitis in this population was 9.5%; 65.9% of affected horses had started a race as three year olds compared to 88.9% of cohorts. Affected horses were older at the time of the first start and had reduced earnings per start. Those with more severe lesions were found to have a significantly greater risk of repeated injury compared to those with milder lesions. Mild lesions did not affect the racing performance as three year olds but more severe lesions resulted in decreased performance as a three year old.

Bottom line: Juvenile racehorses sustaining an insertional suspensory branch injury prior to their first race are likely to perform less well as two year olds and performance as three year olds depends on the severity of the lesion: those with mild lesions perform similarly to controls.